CaIn2S4–In2O3 hybrid nanofibers with expedited photocarrier separation for fast photocatalytic bacterial inactivation under visible light

Abstract

Semiconductor heterostructures are of critical importance in steering the flow of photocarriers (i.e. e⁻ and h⁺). Here, we have fabricated heterostructure-based semiconductor fibers comprising electrospun In₂O₃ nanofibers coaxially wrapped by CaIn₂S₄ nanofoils. The hybrid fibers are characterized by a strong interplay between CaIn₂S₄ and In₂O₃, enabling fast photocarrier separation to generate copious reactive species for disinfection. When illuminated by visible light (λ ≥ 400 nm), the hybrid fibers deliver exceptionally high photocatalytic activity for bacterial inactivation (7 log-reduction in viable cell count for 20 min), well-outcompeting the parent compounds, CaIn₂S₄–In₂O₃ mixtures, and many active photocatalysts reported. The hybrid fibers are type-II semiconductor heterojunctions in nature that can enrich photogenerated e⁻ and h⁺ at the different components of the hybrid fibers. This work justifies the importance of semiconductor heterostructures in guiding photocarrier flows and offers a paradigm for the design of semiconductor hybrid fibers in the area of photocatalytic bacterial inactivation.